Project description:Heat acclimation (AC) allows its faster re-induction following its decline. Constitutively preserved euchromatin state in hsp70 promoter during acclimation decline/regain pushed forward the hypothesis that acclimation decline is a period of “dormant memory” involving molecular program including epigenetic controlled transcriptional regulation leading to heat acclimation mediated cytoprotective memory. We used microarray to uncover hallmark pathways in the induction of heat-acclimation-mediated memory, focusing on markers of epigenetic processes.
Project description:Heat acclimation (AC) allows its faster re-induction following its decline. Constitutively preserved euchromatin state in hsp70 promoter during acclimation decline/regain pushed forward the hypothesis that acclimation decline is a period of M-bM-^@M-^\dormant memoryM-bM-^@M-^] involving molecular program including epigenetic controlled transcriptional regulation leading to heat acclimation mediated cytoprotective memory. We used microarray to uncover hallmark pathways in the induction of heat-acclimation-mediated memory, focusing on markers of epigenetic processes. Rats subjected to heat acclimation, deacclimation, reacclimation and untreated controls were used. We showed here that (i) AC2d provides the molecular switch for acclimation (ii) AC30 heart demonstrates qualitative adaptations (iii) specific molecular program encompassing up/down regulated gene during DeAC, of which epigenetic markers such as class A histones, chromatin modifiers and microRNA suggest epigenetic transcriptional regulation linked to acclimation memory (iv) constitutive upregulation of MAPK P38 module and targets as well as jak/stat and AKT associated pathways during DeAC imply its major role in this process. Noteworthy are players such as poly-(ADP-ribose)polymerase-1 (PARP1) and linker histones (histones H1 cluster in this process).
Project description:The processes of adaptation to environmental heat and aerobic exercise training improve efficiency in various body systems and bring about acclimatory homeostasis. In order to examine the global genomic responses of the soleus and heart following exposure of rats to these stressors, nylon cDNA Atlas Array was used. Male rats were exposed to one of the following stressors: heat acclimation, aerobic training (treadmill), and combined heat acclimation and aerobic training for short (2, 3 days) and long (1 mo) time period. The study comprised seven experimental groups: Controls-untreated. Heat acclimated groups (2dac, Acc)â exposure to environmental heat at 34C for 2 or 30 days. Exercise groups (3dex, Ex)â graduated training protocol under normothermic conditions for 3 and 30 days at 24C. Exercise training and heat acclimation â (3dexac, ExAc)- exposed to both environmental heat and aerobic exercise as above. The Series data tables appended below: 1) Heart - normalized log2 ratio of geomeans defined as treatment/control 2) Soleus - normalized log2 ratio of geomeans defined as treatment/control 21 samples, 3 pool each, of: 1)Â Control untreated rats 2)Â Long-term heat acclimated rats 3)Â Long-term aerobic-exercised trained rats. 4)Â Rats exposed to long-term heat acclimation and exercise training. 5)Â Short term heat acclimated rats. 6)Â Short term aerobic exercised trained rats 7)Â Rats exposed to short-term heat acclimation and exercise training.
Project description:This experiment intended to look for the transcriptome changes that happen in neuronal cells from the preoptic area of the hypothalamus expressing leptin receptors during heat acclimation conditions. 3 groups of animals were used; long-term heat-acclimated animals constantly exposed to 36˚C for 28-35 days, short-term heat-acclimated animals constantly exposed to 36˚C for 5 days, and non-habituated (non-acclimated) animals which were not exposed to heat. The animal line used was LepRCreHTB.
Project description:The processes of adaptation to environmental heat and aerobic exercise training improve efficiency in various body systems and bring about acclimatory homeostasis. In order to examine the global genomic responses of the soleus and heart following exposure of rats to these stressors, nylon cDNA Atlas Array was used. Male rats were exposed to one of the following stressors: heat acclimation, aerobic training (treadmill), and combined heat acclimation and aerobic training for short (2, 3 days) and long (1 mo) time period. The study comprised seven experimental groups: Controls-untreated. Heat acclimated groups (2dac, Acc)– exposure to environmental heat at 34C for 2 or 30 days. Exercise groups (3dex, Ex)– graduated training protocol under normothermic conditions for 3 and 30 days at 24C. Exercise training and heat acclimation – (3dexac, ExAc)- exposed to both environmental heat and aerobic exercise as above. The Series data tables appended below: 1) Heart - normalized log2 ratio of geomeans defined as treatment/control 2) Soleus - normalized log2 ratio of geomeans defined as treatment/control Keywords: stress response
Project description:Intertidal zone organisms can experience transient freezing temperatures during winter low tides, but their extreme cold tolerance mechanisms are not known. Petrolisthes cinctipes is a temperate mid-high intertidal zone crab species that can experience wintertime habitat temperatures below the freezing point of seawater. We examined how cold tolerance changed during the initial phase of thermal acclimation to cold and warm temperatures, as well as the persistence of cold tolerance during long-term thermal acclimation. Thermal acclimation for as little as 6 hours at 8˚C enhanced crab tolerance during a 1h exposure to -2°C relative to crabs acclimated to 18˚C. Potential mechanisms for this enhanced tolerance were elucidated using cDNA microarrays to probe for differences in gene expression in cardiac tissue of warm and cold acclimated crabs during the first day of thermal acclimation. No changes in gene expression were detected until 12h of thermal acclimation. Genes strongly upregulated in warm acclimated crabs represented immune response and extracellular / intercellular processes, suggesting that warm acclimated crabs had a generalized stress response and may have been remodelling tissues or altering intercellular processes. Genes strongly upregulated in cold acclimated crabs included many that are involved in glucose production suggesting that cold acclimation involves increasing intracellular glucose as a cryoprotectant. Structural cytoskeletal proteins were also strongly represented among the genes upregulated in only cold acclimated crabs. There were no consistent changes in composition or the level of unsaturation of membrane phospholipid fatty acids with cold acclimation, which suggests that neither short- nor long-term changes in cold tolerance are mediated by changes in membrane fatty acid composition. Overall, our study demonstrates that initial changes in cold tolerance are likely not regulated by transcriptomic responses, but that gene expression-related changes in homeostasis begin within 12 hours – the length of a tidal cycle. all array data and raw images archived at the Porcelain Crab Array Database (http://array.sfsu.edu)
Project description:We studied the global genomic response in the hypothalamus during heat acclimation, with and without combined hypohydration stress. Rats were acclimated for 2 days or for 30 days at 34°C. Hypohydration (10% decrease in body weight) was attained by water deprivation. Functional analyses demonstrated a bi-phasic acclimatory profile with a transient upregulation of genes encoding ion channels, transporters, and transmitter signaling upon 2 days acclimation, suggesting enhanced neuronal excitability at that acclimation phase. Following long acclimation most genes returned to their pre-acclimation expression levels. In both acclimation phases, genes encoding hormones and neuropeptides, linked with metabolic rate and food intake, were downregulated. The response to hypohydration was characterized by an upregulation of a large number of genes primarily associated with the regulation of ion channels and cell-volume and neuronal excitability. During 2 days acclimation, the response was transiently desensitized, recovering upon LTHA. The results suggest that hypohydration overrides the heat acclimatory status. Keywords: other
Project description:Few studies have assessed the patterns of parasite populations of rodents over a longitudinal gradient in Chile. In this work, the gastrointestinal helminthic fauna of invasive rodents in Chile was examined to assess the association between their presence/absence and abundance with latitude, host sex, and host body condition, and to assess the coexistence and correlation of the abundance between parasite species. Rodents were obtained from 20 localities between 33 and 43°S. Helminths were extracted from the gastrointestinal tract and identified morphologically. Overall, 13 helminth taxa were obtained. The most frequently identified parasite species was Heterakis spumosa, and the most abundant was Syphacia muris, while Physaloptera sp. was the most widely distributed. No locality presented with a coexistence that was different from that expected by chance, while the abundance of five helminthic species correlated with the abundance of another in at least one locality, most likely due to co-infection rather than interaction. Host sex was associated with parasite presence or abundance, and female sex-biased parasitism was notably observed in all cases. Body condition and latitude presented either a positive or negative association with the presence or abundance of parasites depending on the species. It is notable that the likely native Physaloptera sp. is widely distributed among invasive rodents. Further, gravid females were found, suggesting spillback of this species to the native fauna. The low frequency and abundance of highly zoonotic hymenolepid species suggest that rodents are of low concern regarding gastrointestinal zoonotic helminths.